1885.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 177 



±o- / 



\o\. VIII, ]¥o. IS. Wa§hiiagtom, 15. C June I, 1885. 



while iu the species here described the third pera3opods are verj^ much 

 lons^er than the second, the telson is armed with lonjj spiniform lateral 

 processes and movably articulated spines, and the fifth i)era3opods are 

 mucli longer than the fourth. I should regard the equality in the length 

 of the second aud third pairs of pera^opods as an accidental character 

 of the type specimen did not Bate report specimens from various local- 

 ities in the Challenger collections agreeing closely with Dana's descrip- 

 tion and figure. Bate states also that, in his specimens, the petasma 

 (sexual appendage of the first p'eopod of the male) of the left side is 

 longer than that of the right, while the reverse is true of the species 

 here described. 



The carapax and pleon are everywhere densely clothed with short 

 and rather stiff plumose setie. The carapax is about as broad as high 

 and very little compressed anteriorly. There is an incousi)icuous supra- 

 orbital notch, as iu P. consfrictus, and well-developed antennal, hepatic, 

 and branchiostegial spines, the latter forming the an tero inferior angle 

 of the carapax. The sulci are inconspicuous. The dorsum is evenly 

 rounded posteriorly, but rises in a sharp tooth on the gastric region at 

 the base of the rostrum, which rises suddenly above the level of the 

 dorsum, is directed obliquely upward, is shorter than the carapax proper, 

 aud armed above with eight to ten teeth, all of which are over or in 

 front of the orbit. 



The eyes are large, reniform, flattened above, and black. The pedun- 

 cles of the antennulae are nearly as in P. constrictvs^ and the flagella 

 are subequal in length and scarcely longer than the penultimate seg- 

 ment of the peduncle. The antennal scales reach to the tips of the 

 peduncles of the antennse, are about three times as long as broad, regu- 

 larly tapered distally, and the distal portion of the thickened outer 

 margin is armed above with a series of minute spines directed obliquely 

 forward and outward. 



The oral appendages are essentially as in P. longirostris. 



The first and second perteopods are armed with basal spines as in P. 

 constrictuSj and there is in addition a small distal spine on the under 

 side of the ischium in the first, while between the bases of the second 

 there is a jjair of long and very slender spines arising from the sternum 

 and directed forward. The third i)er?eopods reach as far forward as the 

 tip of the rostrum, the full length of the chelse beyond the secou<l pair, 

 and the distal portions are more slender than in the second; the carpus 

 is about once and two -thirds as long as the merus, which is itself about as 

 long as the carpus in the second ; and the chela is scarcely stouter than 

 the carpus and about two-fifths as long. The fourth perjeopods reach 

 about as far forward as the first, while the fifth are conspicuously longer, 

 reaching considerably by the fourth. 

 Proc. ]S"at. Mus. 85 12 



